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The other half of the insect SLC4 family: a Cl/HCO 3 anion exchanger from mosquito renal tubules
Author(s) -
Piermarini Peter M,
Grogan Laura F,
Wang Li,
Beyenbach Klaus W
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.800.4
Subject(s) - malpighian tubule system , dids , xenopus , aedes aegypti , biology , microbiology and biotechnology , biochemistry , botany , membrane , larva , gene , midgut
From the completed genomes of insects it appears that most species possess only two SLC4‐like transporters: ( i ) a Na‐driven Cl/HCO 3 anion exchanger (NDAE) and ( ii ) a putative Cl/HCO 3 anion exchanger (AE). To date, the AE of insects has received little attention compared to the NDAE. The goal of this study was to characterize and localize the SLC4‐like AE expressed in renal (Malpighian) tubules of the yellow‐fever mosquito, Aedes aegypti . Using RT‐PCR on Malpighian tubule cDNA, we identified a full‐length clone ( Aedes AE) that encodes 1,243 amino acids with 40% identity to mammalian AEs. Measurements of intracellular pH (pH i ) in Xenopus oocytes expressing Aedes ‐AE cRNA (AE oocytes) indicate that the rate of pH i recovery after exposure to 5% CO 2 /33 mM HCO 3 is enhanced by lowering extracellular Cl and is blocked by DIDS. No such responses were observed in H 2 O‐injected oocytes subjected to similar treatments. The above experimental manipulations have minor effects on the membrane potential (V m ) of AE and H 2 O‐injected oocytes. A polyclonal antibody raised and affinity purified against the Aedes AE labels the stellate cells, but not principal cells, of Malpighian tubules. Taken together, our results indicate that Aedes Malpighian tubules express a DIDS‐sensitive, electroneutral AE and that the role of this AE in stellate cell function deserves further study. Supported by NIH Grant K01‐DK080194‐01 to PMP.